Here, an electrophotographic image forming apparatus means an apparatus which forms an image on recording medium, with the use of an electrophotographic image forming method. As examples of an electrophotographic image forming apparatus, an electrophotographic copying machine, an electrophotographic printer (for example, laser beam printer, LED printer, etc.), a facsimileing machine, a wordprocessor, etc., can be included.
An image forming apparatus such as an electrophotographic copying machine, a laser beam printer, etc., records an image by selectively exposing numerous points of the uniformly charged photosensitive drum, forming thereby a latent image; developing the latent image with the use of developer, forming an image of the developer; and transferring the image formed of the developer, onto recording medium. This type of image forming apparatus must be supplied with developer each time it runs out of developer. There are roughly two types of a developer supply container for supplying an image forming apparatus with developer: the so-called dumping type, and the cartridge type, that is, the type which is left in the main assembly of an image forming apparatus until it runs out of the developer therein. In the case of the dumping type, the entirety of the developer in the developer supply container is emptied all at once into the buffer portion of the main assembly of the image forming apparatus. In the case of the cartridge type, the developer supply container is mounted into the main assembly of the image forming apparatus to be left therein, and the developer in the developer supply container is gradually released to be supplied to the developing apparatus until the developer supply container becomes depleted of the developer therein.
In recent years, various developer supply containers of the latter type, or the cartridge type, have been proposed from the standpoint of the prevention of the contamination which is liable to occur while supplying an image forming apparatus with developer, and the operability of an image forming apparatus. Some of them are provided with a shutter which is opened or closed to seal or unseal the opening, as the developer outlet, of the container while the container is in the main assembly, and some of them are provided with a stirring member which is disposed in the container to internally convey the developer therein and discharge it while the container is in the main assembly (Patent Document 1).
These proposals make it possible to provide a developer supply container of the cartridge type, which is superior in operability. They also make it possible to prevent the main assembly of an image forming apparatus from being subjected to an excessive amount of load when the main assembly is supplied with developer. Further, they make it possible to simplify a developer supply container itself in structure.
[Patent Document 1: Japanese Patent No. 3408166]
In recent years, however, not only has a compact image forming apparatus main assembly been increasing in demand, but also, the need has been increasing for making compact the developer supplying unit which is for mounting a developer supply container into the main assembly, and also, has the function of supplying the main assembly with the developer in the developer supply container.
However, a developer supply container of the cartridge type, and the developer supplying unit in which a developer supply container of the cartridge type is mounted, are given the function of opening or closing the shutter while the developer supply container is in the main assembly of an image forming apparatus, and the function of moving the stirring member by receiving driving force from the main assembly of an image forming apparatus. Therefore, they are more complicated in mechanical structure, being more difficult to reduce in size, and also, in the space occupied, compared to a developer supply container of the dumping type.
Further, they are limited in terms of the direction from which a developer supply container can be mounted into the main assembly of an image forming apparatus, because of the restrictive relationship between the developer supplying unit and the other units in the internal space of the main assembly, and also, the restriction arising from the limitation in the size of the space necessary to set the main assembly (which includes not only the actual size of the main assembly, but also, the size of the space necessary for opening or closing the cover thereof, space necessary for replacing a disposable member, for example, a developer supply container, etc.). Moreover, there is the restriction regarding the visibility of a developer supply container and the developer supplying unit during the mounting of the developer supply container, and/or the posture which an operator is required to assume to mount a developer supply container into the main assembly, or remove it therefrom, that is, whether or not a user can replace a developer supply container while standing upright. In other words, there are various restrictions regarding the design of the main assembly of an image forming apparatus, in particular, the direction from which the main assembly of an image forming apparatus can be accessed for the mounting of a developer supply container. From the standpoint of being superior in the posture which a user is required to assume to operate an image forming apparatus, there is high demand for such a design that allows a developer supply container to be mounted into the image forming apparatus main assembly from above.
In other words, the employment of a developer supply container of the cartridge type and the developer supplying unit therefore tends to reduce the main assembly of an image forming apparatus in terms of the latitude in its design: a designer of the main assembly of an image forming apparatus is forced to design the main assembly so that the main assembly can be accessed from above for the installation and replacement of a developer supply container.
Thus, there have been designed various developer supply containers of the cartridge type, which can deal with the concerns regarding the direction from which a developer supply container can be mounted into the main assembly of an image forming apparatus while meeting the above described demands. However, it has been found that they suffer from the following problems.
The first problem is: In order to position the portion of the driving force transmitting mechanism for transmitting the force for opening or closing the aforementioned shutter, and the portion of the driving force transmitting mechanism for receiving the force for driving the aforementioned stirring member, on the same side (surface) of a developer supply container, it is necessary for the two driving transmitting mechanisms of the main assembly of an image forming apparatus to be placed close to each other. Thus, this design is limited in terms of the extent of size reduction, in consideration of the interference among the driving force transmission mechanisms on the main assembly side, and the like factors. Further, the developer supply container side has a problem similar to the above described problem of the main assembly. That is, it is extremely difficult to position the two driving force transferring portions, that is, the stirring member driving force receiving portion and shutter driving force transmitting portion, of a developer supply container, on one of the surfaces of the developer supply container designed for compactness, while taking into consideration the interference between the stirring member driving force receiving portion and shutter driving force transmitting portion of the developer supply container, and the driving mechanism on the main assembly side, which is likely to occur during the installation or removal of the developer supply container.
The second problem is: The image forming apparatus and developer supply containers were structured so that the developer supply containers are mounted into the main assembly of an image forming apparatus from such a direction that as they are mounted into the main assembly, they are subjected to the reactive forces which occur in each of the driving portions. Therefore, in order to prevent such operational errors as pulling a developer supply container out of the main assembly when opening or closing the shutter after the mounting of the developer supply container into the main assembly, or while the stirring member is receiving the force for driving it, it was necessary to provide an independent means for regulating the movement of a developer supply container in the direction in which a developer supply container is to be removed from, or mounted into, the main assembly. In particular, in the case that the transmission of driving force is accomplished by the meshing of the meshing of the gears, as the driving force is transmitted from one gear to the other, reactive force is generated in the direction to separate the two gears (in the direction to increase the distance between the rotational axes of the two gears). Therefore, unless the shifting of the two gears is regulated, it is possible that tooth skipping or the like occurs between the two gears, inviting such problems as unsatisfactory stirring of the developer, unsatisfactory opening of the shutter, or the like.
For example, in the case of a developer supply container such as the one disclosed in the referential document quoted in the background technology section of this document, when the stirring member is rotationally driven, and also, when the shutter is opened or closed, a developer supply container is subjected to the reactive force which is generated by the driving portions in the direction perpendicular to the direction in which a developer supply container is mounted into the main assembly. However, this movement of a developer supply container, which is likely to be caused by the abovementioned reactive force from the driving portion as soon as the developer supply contain is mounted, can be prevented by the guides or the like, with which the developer supply container accommodating portion of the main assembly is provided. Therefore, problems such as the above described ones did not occur.